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Clinical Research

Pediatric Walking Speed Normal Reference Values in a Local Population

Cadieux JM, Pyhala SL, Johnson JV

Pediatric Physical Therapy, 2023;35(3):326-331

doi:10.1097/PEP.0000000000001015

My Role: Statistical analysis and methodology (third author)

Methods: R (version 4.1.3), IBM SPSS

Analysis: 13×2×2 factorial ANOVA with Type III sum of squares, 1,593 participants ages 5-17

Impact: Normative reference values for assessing children with disabilities in rural Alaska school district

Interdisciplinary collaboration applying statistical methods to clinical physical therapy research. Large dataset management (1,593 children) and rigorous factorial analysis examining main effects and two-way interactions for age, sex, and footwear.

Pure Mathematics

Spectral Conditions for Composition Operators on Algebras of Functions

Johnson J, Tonev T

Communications in Mathematics and Applications, 2012;3(1)

Research on spectral preserving maps between function algebras. Extends results on composition operators in commutative Banach algebras. Co-authored with dissertation advisor.

Ph.D. Dissertation (2013)

Peripherally-Multiplicative Spectral Preservers Between Function Algebras

University of Montana, Missoula, MT

Advisor: Dr. Thomas Tonev

Field: Commutative Banach Algebras, Functional Analysis

Established general sufficient conditions for maps between function algebras to be composition or weighted composition operators. Defined and characterized weakly peripherally-multiplicative and almost peripherally-multiplicative maps. Extended theory to function algebras without unit on locally compact Hausdorff spaces.

Theoretical Computer Science Exploration

Active learning through collaborative study, 2023–Present

Student Collaboration

Lukas Renner (MIT early admission candidate)

Format: Collaborative exploration, 2-3 meetings/week, 1+ year

"Much of the time, we were learning together"

Topics Explored

Theoretical Foundations

  • Lambda calculus and mathematical representation
  • Formal languages and automata theory
  • Propositional logic and proof systems

Abstract Algebra

  • Field and ring theory
  • Galois fields (cryptographic applications)
  • Quotient objects and representatives

Applied Cryptography

  • Elliptic curve cryptography
  • Mathematical representations in finite fields
  • Implementation considerations (student's Rust work)

Computational Mathematics

  • Computational linear algebra
  • Matrix operations and performance
  • Dimension and complexity constraints

Theory Informing Practice

These explorations directly inform implementation work:

  • Abstract algebra → cryptographic implementations
  • Lambda calculus → functional paradigms in distributed systems
  • Category theory → composable system design
  • Formal methods → policy verification (MAAT Framework)

Education

Ph.D. Mathematical Sciences

University of Montana, 2008–2013

Advisor: Dr. Thomas Tonev

Commutative Banach Algebras, Functional Analysis

M.S. Coursework — Mathematical Modeling

Humboldt State University, 2004–2005

Environmental Systems

B.A. Mathematics

Humboldt State University, 2002–2004

Continuing Education

  • Machine Learning (completed with certificate) — Andrew Ng, Stanford University/Coursera. Supervised learning, neural networks, unsupervised learning, ML system design.
  • OLC Online Teaching Certificate Program (2019) — Foundations + electives (retention strategies, gamification, accessibility). Applied to Applied Calculus online course.
  • AARMS Graduate Summer School (2010) — Atlantic Association of Research and Mathematical Sciences. University of New Brunswick, Canada. Courses: Topological Combinatorics, Algebraic Topology.
  • Function Spaces and Lineability IX (2015) — Spring School on Analysis, Charles University, Czech Republic.